[PATCH net-next 1/3] ptp: introduce ptp_cancel_worker_sync

[Vladimir Oltean <olteanv@gmail.com>]

In order to effectively use the PTP kernel thread for tasks such as
timestamping packets, allow the user control over stopping it, which is
needed e.g. when the timestamping queues must be drained.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
---
 drivers/ptp/ptp_clock.c          | 6 ++++++
 include/linux/ptp_clock_kernel.h | 7 +++++++
 2 files changed, 13 insertions(+)

diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index e60eab7f8a61..4f0d91a76dcb 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -371,6 +371,12 @@ int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
 }
 EXPORT_SYMBOL(ptp_schedule_worker);
 
+void ptp_cancel_worker_sync(struct ptp_clock *ptp)
+{
+	kthread_cancel_delayed_work_sync(&ptp->aux_work);
+}
+EXPORT_SYMBOL(ptp_cancel_worker_sync);
+
 /* module operations */
 
 static void __exit ptp_exit(void)
diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index 93cc4f1d444a..083e32a5e456 100644
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -243,6 +243,13 @@ int ptp_find_pin(struct ptp_clock *ptp,
 
 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay);
 
+/**
+ * ptp_cancel_worker_sync() - cancel ptp auxiliary clock
+ *
+ * @ptp:     The clock obtained from ptp_clock_register().
+ */
+void ptp_cancel_worker_sync(struct ptp_clock *ptp);
+
 #else
 static inline struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 						   struct device *parent)
-- 
2.17.1